1 Introduction

Formlets are a way of building HTML forms that are type-safe, handle errors, abstract and are easy to combine into bigger forms. Here's an example:

name :: Form String
name = input Nothing

The input function takes a Maybe String, and produces a XHtmlForm String. The Maybe String is used for default values. If you give it a nothing, it won't have a default value. If you pass in a (Just "value"), it will be pre-populated with the value "value".

You can easily combine formlets using the Applicative Functor combinators. Suppose you have a User-datatype: